Interpretive Summary: USA cotton production has become more reliant on export of raw cotton fibers for a market. Foreign markets emphasize fiber quality more than domestic one. However, there is a lack of high fiber quality in high yielding cultivars, especially in the southeastern region. Broadening the genetic base in cotton cultivars is essential for genetic improvement of fiber quality while maintaining productivity and profits for growers. An exotic germplasm population derived from multiple crosses between G. hirsutum and G. barbadense was evaluated for yield and fiber quality. Tremendous genetic diversity for lint yield and fiber quality was identified in this population. This diversity is useful for selection of elite breeding lines for yield and fiber quality. The results will help cotton geneticists develop high yielding cultivars with better fiber quality.

Technical Abstract:
Broadening the genetic base is essential for genetic improvement of lint yield and fiber quality in upland cotton. An exotic germplasm population derived from multiple crosses between Gossypium barbadense L. and G. hirsutum was obtained from USDA-ARS at Las Cruces, NM. This germplasm was designated as JC for the originator, John Cotton. Two hundred JC lines and five check cultivars were planted at two locations in 2006 and one location in 2007 with two replicates each. Significant (P=0.001) genotypic variation for yield and fiber quality was identified. Interactions between genotype and environment for yield and fiber quality were small relative to the genotypic effects. Wide ranges of yield and fiber properties were identified. Genotypic correlations between yield parameters and fiber properties and their standard errors were estimated by Multivariate Restricted Maximum Likelihood analysis. Lint yield was negatively associated with fiber quality. Lint per seed was favorably correlated with lint percent, elongation, span lengths, and fineness. Fiber strength was favorably correlated with 50% span length (r=0.68), 2.5% span length (r=0.15), short fiber content (r=-0.62), and fineness (r=-0.38). Short fiber content was negatively correlated with fineness (r=-0.38). This relation was superimposed by their high significant (P=0.001) correlations with maturity. Short fiber content was negatively correlated with maturity ratio (r=-0.75) while fineness was positively correlated with maturity ratio (r=0.81). These results indicate that JC germplasm is a useful genetic resource for genetic lint yield and fiber quality improvement.